File:A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine (1890) (14576643158).jpg

Identifier: textbookofcompar00mill (find matches)
Title: A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine
Year: 1890 (1890s)
Authors: Mills, Wesley, 1847-1915
Subjects: Physiology, Comparative
Publisher: New York, London, D. Appleton and company
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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Fig. 05.—The cleavage of a frogs egg (10 times enlarged). A, the parent-cell; B, thefirst two cleavage-cells; 0.4 cells; D, 8 cells (4 animal and 4 vegetative); E. 12cells (8 animal and 4 vegetative); F, 16 cells (8 animal and 8 vegetative); G, 24cells (1(5 animal and 8 vegetative); H, 32 cells: /. 48 cells; A. 04 cell^: L. 96 eleav-age-cclls; .)/, mo cleavage-cells (128 animal and 32 vegetative). (Haeckel.) of segments, at least up to the point when a large number hasbeen formed. This is rather to be considered as a type of one 68 COMPARATIVE PHYSIOLOGY. form of segmentation than as applicable to all, for even atthis early stage differences are to be noted in the mode of seg-mentation wbich characterize effectually certain groups of ani-mals ; but in all there is segmentation, and that segmentationis rhythmical. Segmentation results in the formation of a multicellularaggregation which, sooner or later, incloses a central cavity(segmentation cavity, blastocele). Usually this cell ag

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